The constant maintenance of a small squadron in the Mediterranean is a necessary substitute for the humiliating alternative of paying tribute for the security of our commerce in that sea, and for a precarious peace, at the mercy of every caprice of four Barbary States, by whom it was liable to be violated. An additional motive for keeping a respectable force stationed there at this time is found in the maritime war raging between the Greeks and the Turks, and in which the neutral navigation of this Union is always in danger of outrage and depredation. A few instances have occurred of such depredations upon our merchant vessels by privateers or pirates wearing the Grecian flag, but without real authority from the Greek or any other Government. The heroic struggles of the Greeks themselves, in which our warmest sympathies as freemen and Christians have been engaged, have continued to be maintained with vicissitudes of success adverse and favorable. Similar motives have rendered expedient the keeping of a like force on the coasts of Peru and Chile on the Pacific. The irregular and convulsive character of the war upon the shores has been extended to the conflicts upon the ocean. An active warfare has been kept up for years with alternate success, though generally to the advantage of the American patriots. But their naval forces have not always been under the control of their own Governments. Blockades, unjustifiable upon any acknowledged principles of international law, have been proclaimed by officers in command, and though disavowed by the supreme authorities, the protection of our own commerce against them has been made cause of complaint and erroneous imputations against some of the most gallant officers of our Navy. Complaints equally groundless have been made by the commanders of the Spanish royal forces in those seas; but the most effective protection to our commerce has been the flag and the firmness of our own commanding officers. The cessation of the war by the complete triumph of the patriot cause has removed, it is hoped, all cause of dissension with one party and all vestige of force of the other. But an unsettled coast of many degrees of latitude forming a part of our own territory and a flourishing commerce and fishery extending to the islands of the Pacific and to China still require that the protecting power of the Union should be displayed under its flag as well upon the ocean as upon the land.